Internet Gaming Addiction in Male Adolescents: Mitochondrial DNA Variations and Leukocyte Telomere Length

Mitochondrial DNA (mtDNA) variations are linked to psychiatric disorders, but their association with internet gaming addiction (IGA) remains unexplored. We investigated mitochondrial D-loop D310 and D514 regions and mtDNA copy number (mtCN) in male adolescents with and without IGA, exploring their associations with leukocyte telomere length (LTL).

Questionnaires assessed IGA in 206 male adolescents. Blood samples were analyzed for (C)_n repeats at D310 and (CA)_n repeats at D514. Relative mtCN and LTL were measured using quantitative PCR.

D310 polymorphism distribution differed significantly between the IGA and non-IGA groups (p = 0.040). Among the (C)_n repeats, (C)₈ frequency at D310 was significantly lower in the IGA group than in the non-IGA group (p = 0.017). Multivariable logistic regression initially identified the (C)₈ polymorphism as an independent predictor reducing IGA likelihood (OR = 0.474, p = 0.014), although this nominal association did not remain statistically significant after formal Bonferroni correction. mtCN differences were not significant (p = 0.247). Notably, LTL was significantly shorter in the IGA group among carriers of (C)₈ and (CA)₅ polymorphisms (both p = 0.001). Multivariable linear regression confirmed that IGA remained robustly associated with shorter LTL (B = -40.180, p < 0.001), while (C)₈ and (CA)₅ repeats were not independently associated with LTL shortening.

While the (C)₈ polymorphism's direct genetic contribution to IGA susceptibility remains preliminary and hypothesis-generating due to multiple testing attenuation, IGA exhibits a robust, independent association with LTL shortening. Mitochondrial genomic backgrounds may play a subtle, modulatory role in behavioral addiction pathways, warranting further longitudinal validation.